Introduction

A Valve element represents a component that will be
inserted into the request processing pipeline for the associated
Catalina container (Engine,
Host, or Context).
Individual Valves have distinct processing capabilities, and are
described individually below.

The description below uses the variable name $CATALINA_BASE to refer the
base directory against which most relative paths are resolved. If you have
not configured Tomcat for multiple instances by setting a CATALINA_BASE
directory, then $CATALINA_BASE will be set to the value of $CATALINA_HOME,
the directory into which you have installed Tomcat.

Access Logging

Access logging is performed by valves that implement
org.apache.catalina.AccessLog interface.

Access Log Valve

Introduction

The Access Log Valve creates log files in the
same format as those created by standard web servers. These logs
can later be analyzed by standard log analysis tools to track page
hit counts, user session activity, and so on. This Valve
uses self-contained logic to write its log files, which can be
automatically rolled over at midnight each day. (The essential
requirement for access logging is to handle a large continuous
stream of data with low overhead. This Valve does not
use Apache Commons Logging, thus avoiding additional overhead and
potentially complex configuration).

This Valve may be associated with any Catalina container
(Context, Host, or Engine), and
will record ALL requests processed by that container.

Some requests may be handled by Tomcat before they are passed to a
container. These include redirects from /foo to /foo/ and the rejection of
invalid requests. Where Tomcat can identify the Context that
would have handled the request, the request/response will be logged in the
AccessLog(s) associated Context, Host
and Engine. Where Tomcat cannot identify the
Context that would have handled the request, e.g. in cases
where the URL is invalid, Tomcat will look first in the Engine,
then the default Host for the Engine and finally
the ROOT (or default) Context for the default Host
for an AccessLog implementation. Tomcat will use the first
AccessLog implementation found to log those requests that are
rejected before they are passed to a container.

The output file will be placed in the directory given by the
directory attribute. The name of the file is composed
by concatenation of the configured prefix, timestamp and
suffix. The format of the timestamp in the file name can be
set using the fileDateFormat attribute. This timestamp will
be omitted if the file rotation is switched off by setting
rotatable to false.

Warning: If multiple AccessLogValve instances
are used, they should be configured to use different output files.

If sendfile is used, the response bytes will be written asynchronously
in a separate thread and the access log valve will not know how many bytes
were actually written. In this case, the number of bytes that was passed to
the sendfile thread for writing will be recorded in the access log valve.

Attributes

The Access Log Valve supports the following
configuration attributes:

Attribute

Description

buffered

Flag to determine if logging will be buffered.
If set to false, then access logging will be written after each
request. Default value: true

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.AccessLogValve to use the
default access log valve.

condition

The same as conditionUnless. This attribute is
provided for backwards compatibility.

conditionIf

Turns on conditional logging. If set, requests will be
logged only if ServletRequest.getAttribute() is
not null. For example, if this value is set to
important, then a particular request will only be logged
if ServletRequest.getAttribute("important") != null.
The use of Filters is an easy way to set/unset the attribute
in the ServletRequest on many different requests.

conditionUnless

Turns on conditional logging. If set, requests will be
logged only if ServletRequest.getAttribute() is
null. For example, if this value is set to
junk, then a particular request will only be logged
if ServletRequest.getAttribute("junk") == null.
The use of Filters is an easy way to set/unset the attribute
in the ServletRequest on many different requests.

directory

Absolute or relative pathname of a directory in which log files
created by this valve will be placed. If a relative path is
specified, it is interpreted as relative to $CATALINA_BASE. If
no directory attribute is specified, the default value is "logs"
(relative to $CATALINA_BASE).

encoding

Character set used to write the log file. An empty string means
to use the system default character set. Default value: use the
system default character set.

fileDateFormat

Allows a customized timestamp in the access log file name.
The file is rotated whenever the formatted timestamp changes.
The default value is .yyyy-MM-dd.
If you wish to rotate every hour, then set this value
to .yyyy-MM-dd.HH.
The date format will always be localized
using the locale en_US.

ipv6Canonical

Flag to determine if IPv6 addresses should be represented in canonical
representation format as defined by RFC 5952. If set to true,
then IPv6 addresses will be written in canonical format (e.g.
2001:db8::1:0:0:1, ::1), otherwise it will be
represented in full form (e.g. 2001:db8:0:0:1:0:0:1,
0:0:0:0:0:0:0:1). Default value: false

locale

The locale used to format timestamps in the access log
lines. Any timestamps configured using an
explicit SimpleDateFormat pattern (%{xxx}t)
are formatted in this locale. By default the
default locale of the Java process is used. Switching the
locale after the AccessLogValve is initialized is not supported.
Any timestamps using the common log format
(CLF) are always formatted in the locale
en_US.

maxDays

The maximum number of days rotated access logs will be retained for
before being deleted. If not specified, the default value of
-1 will be used which means never delete old files.

maxLogMessageBufferSize

Log message buffers are usually recycled and re-used. To prevent
excessive memory usage, if a buffer grows beyond this size it will be
discarded. The default is 256 characters. This should be
set to larger than the typical access log message size.

pattern

A formatting layout identifying the various information fields
from the request and response to be logged, or the word
common or combined to select a
standard format. See below for more information on configuring
this attribute.

prefix

The prefix added to the start of each log file's name. If not
specified, the default value is "access_log".

renameOnRotate

By default for a rotatable log the active access log file name
will contain the current timestamp in fileDateFormat.
During rotation the file is closed and a new file with the next
timestamp in the name is created and used. When setting
renameOnRotate to true, the timestamp
is no longer part of the active log file name. Only during rotation
the file is closed and then renamed to include the timestamp.
This is similar to the behavior of most log frameworks when
doing time based rotation.
Default value: false

requestAttributesEnabled

Set to true to check for the existence of request
attributes (typically set by the RemoteIpValve and similar) that should
be used to override the values returned by the request for remote
address, remote host, server port and protocol. If the attributes are
not set, or this attribute is set to false then the values
from the request will be used. If not set, the default value of
false will be used.

resolveHosts

This attribute is no longer supported. Use the connector
attribute enableLookups instead.

If you have enableLookups on the connector set to
true and want to ignore it, use %a instead of
%h in the value of pattern.

rotatable

Flag to determine if log rotation should occur.
If set to false, then this file is never rotated and
fileDateFormat is ignored.
Default value: true

suffix

The suffix added to the end of each log file's name. If not
specified, the default value is "" (a zero-length string),
meaning that no suffix will be added.

Values for the pattern attribute are made up of literal
text strings, combined with pattern identifiers prefixed by the "%"
character to cause replacement by the corresponding variable value from
the current request and response. The following pattern codes are
supported:

%a - Remote IP address

%A - Local IP address

%b - Bytes sent, excluding HTTP headers, or '-' if zero

%B - Bytes sent, excluding HTTP headers

%h - Remote host name (or IP address if
enableLookups for the connector is false)

%H - Request protocol

%l - Remote logical username from identd (always returns
'-')

%m - Request method (GET, POST, etc.)

%p - Local port on which this request was received.
See also %{xxx}p below.

%q - Query string (prepended with a '?' if it exists)

%r - First line of the request (method and request URI)

%s - HTTP status code of the response

%S - User session ID

%t - Date and time, in Common Log Format

%u - Remote user that was authenticated (if any), else '-'

%U - Requested URL path

%v - Local server name

%D - Time taken to process the request, in millis

%T - Time taken to process the request, in seconds

%F - Time taken to commit the response, in millis

%I - Current request thread name (can compare later with stacktraces)

%X - Connection status when response is completed:

X = Connection aborted before the response completed.

+ = Connection may be kept alive after the response is sent.

- = Connection will be closed after the response is sent.

There is also support to write information incoming or outgoing
headers, cookies, session or request attributes and special
timestamp formats.
It is modeled after the
Apache HTTP Server log configuration
syntax. Each of them can be used multiple times with different xxx keys:

The shorthand pattern pattern="combined"
appends the values of the Referer and User-Agent
headers, each in double quotes, to the common pattern.

When Tomcat is operating behind a reverse proxy, the client information
logged by the Access Log Valve may represent the reverse proxy, the browser
or some combination of the two depending on the configuration of Tomcat and
the reverse proxy. For Tomcat configuration options see
Proxies Support and the
Proxy How-To. For reverse proxies that
use mod_jk, see the generic
proxy documentation. For other reverse proxies, consult their
documentation.

Extended Access Log Valve

Introduction

The Extended Access Log Valve extends the
Access Log Valve class, and so
uses the same self-contained logging logic. This means it
implements many of the same file handling attributes. The main
difference to the standard AccessLogValve is that
ExtendedAccessLogValve creates log files which
conform to the Working Draft for the
Extended Log File Format
defined by the W3C.

Attributes

The Extended Access Log Valve supports all
configuration attributes of the standard
Access Log Valve. Only the
values used for className and pattern differ.

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.ExtendedAccessLogValve to
use the extended access log valve.

pattern

A formatting layout identifying the various information fields
from the request and response to be logged.
See below for more information on configuring this attribute.

Values for the pattern attribute are made up of
format tokens. Some of the tokens need an additional prefix. Possible
prefixes are c for "client", s for "server",
cs for "client to server", sc for
"server to client" or x for "application specific".
Furthermore some tokens are completed by an additional selector.
See the W3C specification
for more information about the format.

The following format tokens are supported:

bytes - Bytes sent, excluding HTTP headers, or '-' if zero

c-dns - Remote host name (or IP address if
enableLookups for the connector is false)

c-ip - Remote IP address

cs-method - Request method (GET, POST, etc.)

cs-uri - Request URI

cs-uri-query - Query string (prepended with a '?' if it exists)

cs-uri-stem - Requested URL path

date - The date in yyyy-mm-dd format for GMT

s-dns - Local host name

s-ip - Local IP address

sc-status - HTTP status code of the response

time - Time the request was served in HH:mm:ss format for GMT

time-taken - Time (in seconds as floating point) taken to serve the request

x-threadname - Current request thread name (can compare later with stacktraces)

For any of the x-H(XXX) the following method will be called from the
HttpServletRequest object:

x-H(authType): getAuthType

x-H(characterEncoding): getCharacterEncoding

x-H(contentLength): getContentLength

x-H(locale): getLocale

x-H(protocol): getProtocol

x-H(remoteUser): getRemoteUser

x-H(requestedSessionId): getRequestedSessionId

x-H(requestedSessionIdFromCookie):
isRequestedSessionIdFromCookie

x-H(requestedSessionIdValid):
isRequestedSessionIdValid

x-H(scheme): getScheme

x-H(secure): isSecure

There is also support to write information about headers
cookies, context, request or session attributes and request
parameters.

cs(XXX) for incoming request headers with name XXX

sc(XXX) for outgoing response headers with name XXX

x-A(XXX) for the servlet context attribute with name XXX

x-C(XXX) for the first cookie with name XXX

x-O(XXX) for a concatenation of all outgoing response headers with name XXX

x-P(XXX) for the URL encoded (using UTF-8) request parameter with name XXX

x-R(XXX) for the request attribute with name XXX

x-S(XXX) for the session attribute with name XXX

Access Control

Remote Address Valve

Introduction

The Remote Address Valve allows you to compare the
IP address of the client that submitted this request against one or more
regular expressions, and either allow the request to continue
or refuse to process the request from this client. A Remote Address
Valve can be associated with any Catalina container
(Engine, Host, or
Context), and must accept any request
presented to this container for processing before it will be passed on.

The syntax for regular expressions is different than that for
'standard' wildcard matching. Tomcat uses the java.util.regex
package. Please consult the Java documentation for details of the
expressions supported.

Optionally one can append the server connector port separated with a
semicolon (";") to allow different expressions for each connector.

The behavior when a request is refused can be changed
to not deny but instead set an invalid authentication
header. This is useful in combination with the context attribute
preemptiveAuthentication="true".

Note: There is a caveat when using this valve with
IPv6 addresses. Format of the IP address that this valve is processing
depends on the API that was used to obtain it. If the address was obtained
from Java socket using Inet6Address class, its format will be
x:x:x:x:x:x:x:x. That is, the IP address for localhost
will be 0:0:0:0:0:0:0:1 instead of the more widely used
::1. Consult your access logs for the actual value.

Attributes

The Remote Address Valve supports the following
configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.RemoteAddrValve.

allow

A regular expression (using java.util.regex) that the
remote client's IP address is compared to. If this attribute
is specified, the remote address MUST match for this request to be
accepted. If this attribute is not specified, all requests will be
accepted UNLESS the remote address matches a deny
pattern.

deny

A regular expression (using java.util.regex) that the
remote client's IP address is compared to. If this attribute
is specified, the remote address MUST NOT match for this request to be
accepted. If this attribute is not specified, request acceptance is
governed solely by the allow attribute.

denyStatus

HTTP response status code that is used when rejecting denied
request. The default value is 403. For example,
it can be set to the value 404.

addConnectorPort

Append the server connector port to the client IP address separated
with a semicolon (";"). If this is set to true, the
expressions configured with allow and
deny is compared against ADDRESS;PORT
where ADDRESS is the client IP address and
PORT is the Tomcat connector port which received the
request. The default value is false.

invalidAuthenticationWhenDeny

When a request should be denied, do not deny but instead
set an invalid authentication header. This only works
if the context has the attribute preemptiveAuthentication="true"
set. An already existing authentication header will not be
overwritten. In effect this will trigger authentication instead of deny
even if the application does not have a security constraint configured.

This can be combined with addConnectorPort to trigger authentication
depending on the client and the connector that is used to access an application.

Remote Host Valve

Introduction

The Remote Host Valve allows you to compare the
hostname of the client that submitted this request against one or more
regular expressions, and either allow the request to continue
or refuse to process the request from this client. A Remote Host
Valve can be associated with any Catalina container
(Engine, Host, or
Context), and must accept any request
presented to this container for processing before it will be passed on.

The syntax for regular expressions is different than that for
'standard' wildcard matching. Tomcat uses the java.util.regex
package. Please consult the Java documentation for details of the
expressions supported.

Optionally one can append the server connector port separated with a
semicolon (";") to allow different expressions for each connector.

The behavior when a request is refused can be changed
to not deny but instead set an invalid authentication
header. This is useful in combination with the context attribute
preemptiveAuthentication="true".

Note: This valve processes the value returned by
method ServletRequest.getRemoteHost(). To allow the method
to return proper host names, you have to enable "DNS lookups" feature on
a Connector.

Attributes

The Remote Host Valve supports the following
configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.RemoteHostValve.

allow

A regular expression (using java.util.regex) that the
remote client's hostname is compared to. If this attribute
is specified, the remote hostname MUST match for this request to be
accepted. If this attribute is not specified, all requests will be
accepted UNLESS the remote hostname matches a deny
pattern.

deny

A regular expression (using java.util.regex) that the
remote client's hostname is compared to. If this attribute
is specified, the remote hostname MUST NOT match for this request to be
accepted. If this attribute is not specified, request acceptance is
governed solely by the allow attribute.

denyStatus

HTTP response status code that is used when rejecting denied
request. The default value is 403. For example,
it can be set to the value 404.

addConnectorPort

Append the server connector port to the client hostname separated
with a semicolon (";"). If this is set to true, the
expressions configured with allow and
deny is compared against HOSTNAME;PORT
where HOSTNAME is the client hostname and
PORT is the Tomcat connector port which received the
request. The default value is false.

invalidAuthenticationWhenDeny

When a request should be denied, do not deny but instead
set an invalid authentication header. This only works
if the context has the attribute preemptiveAuthentication="true"
set. An already existing authentication header will not be
overwritten. In effect this will trigger authentication instead of deny
even if the application does not have a security constraint configured.

This can be combined with addConnectorPort to trigger authentication
depending on the client and the connector that is used to access an application.

Remote CIDR Valve

Introduction

The Remote CIDR Valve allows you to compare the
IP address of the client that submitted this request against one or more
netmasks following the CIDR notation, and either allow the request to
continue or refuse to process the request from this client. IPv4 and
IPv6 are both fully supported. A Remote CIDR Valve can be associated
with any Catalina container (Engine,
Host, or Context), and
must accept any request presented to this container for processing before
it will be passed on.

This valve mimicks Apache's Order,
Allow from and Deny from directives,
with the following limitations:

Order will always be allow, deny;

dotted quad notations for netmasks are not supported (that is, you
cannot write 192.168.1.0/255.255.255.0, you must write
192.168.1.0/24;

shortcuts, like 10.10., which is equivalent to
10.10.0.0/16, are not supported;

as the valve name says, this is a CIDR only valve,
therefore subdomain notations like .mydomain.com are not
supported either.

Some more features of this valve are:

if you omit the CIDR prefix, this valve becomes a single IP
valve;

unlike the Remote Host Valve,
it can handle IPv6 addresses in condensed form (::1,
fe80::/71, etc).

Attributes

The Remote CIDR Valve supports the following
configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.RemoteCIDRValve.

allow

A comma-separated list of IPv4 or IPv6 netmasks or addresses
that the remote client's IP address is matched against.
If this attribute is specified, the remote address MUST match
for this request to be accepted. If this attribute is not specified,
all requests will be accepted UNLESS the remote IP is matched by a
netmask in the deny attribute.

deny

A comma-separated list of IPv4 or IPv6 netmasks or addresses
that the remote client's IP address is matched against.
If this attribute is specified, the remote address MUST NOT match
for this request to be accepted. If this attribute is not specified,
request acceptance is governed solely by the accept
attribute.

Example

Proxies Support

Load Balancer Draining Valve

Introduction

When using mod_jk or mod_proxy_ajp, the client's session id is used to
determine which back-end server will be used to serve the request. If the
target node is being "drained" (in mod_jk, this is the DISABLED
state; in mod_proxy_ajp, this is the Drain (N) state), requests
for expired sessions can actually cause the draining node to fail to
drain.

Unfortunately, AJP-based load-balancers cannot prove whether the
client-provided session id is valid or not and therefore will send any
requests for a session that appears to be targeted to that node to the
disabled (or "draining") node, causing the "draining" process to take
longer than necessary.

This Valve detects requests for invalid sessions, strips the session
information from the request, and redirects back to the same URL, where
the load-balancer should choose a different (active) node to handle the
request. This will accelerate the "draining" process for the disabled
node(s).

The activation state of the node is sent by the load-balancer in the
request, so no state change on the node being disabled is necessary. Simply
configure this Valve in your valve pipeline and it will take action when
the activation state is set to "disabled".

You should take care to register this Valve earlier in the Valve pipeline
than any authentication Valves, because this Valve should be able to
redirect a request before any authentication Valve saves a request to a
protected resource. If this happens, a new session will be created and
the draining process will stall because a new, valid session will be
established.

Attributes

The Load Balancer Draining Valve supports the
following configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.LoadBalancerDrainingValve.

redirectStatusCode

Allows setting a custom redirect code to be used when the client
is redirected to be re-balanced by the load-balancer. The default is
307 TEMPORARY_REDIRECT.

ignoreCookieName

When used with ignoreCookieValue, a client can present
this cookie (and accompanying value) that will cause this Valve to
do nothing. This will allow you to probe your disabled node
before re-enabling it to make sure that it is working as expected.

ignoreCookieValue

When used with ignoreCookieName, a client can present
a cookie (and accompanying value) that will cause this Valve to
do nothing. This will allow you to probe your disabled node
before re-enabling it to make sure that it is working as expected.

Remote IP Valve

Introduction

Tomcat port of
mod_remoteip,
this valve replaces the apparent client remote IP address and hostname for
the request with the IP address list presented by a proxy or a load balancer
via a request headers (e.g. "X-Forwarded-For").

Another feature of this valve is to replace the apparent scheme
(http/https), server port and request.secure with the scheme presented
by a proxy or a load balancer via a request header
(e.g. "X-Forwarded-Proto").

This Valve may be used at the Engine, Host or
Context level as required. Normally, this Valve would be used
at the Engine level.

If used in conjunction with Remote Address/Host valves then this valve
should be defined first to ensure that the correct client IP address is
presented to the Remote Address/Host valves.

Note: By default this valve has no effect on the
values that are written into access log. The original values are restored
when request processing leaves the valve and that always happens earlier
than access logging. To pass the remote address, remote host, server port
and protocol values set by this valve to the access log,
they are put into request attributes. Publishing these values here
is enabled by default, but AccessLogValve should be explicitly
configured to use them. See documentation for
requestAttributesEnabled attribute of
AccessLogValve.

The names of request attributes that are set by this valve
and can be used by access logging are the following:

org.apache.catalina.AccessLog.RemoteAddr

org.apache.catalina.AccessLog.RemoteHost

org.apache.catalina.AccessLog.Protocol

org.apache.catalina.AccessLog.ServerPort

org.apache.tomcat.remoteAddr

Attributes

The Remote IP Valve supports the
following configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.RemoteIpValve.

remoteIpHeader

Name of the HTTP Header read by this valve that holds the list of
traversed IP addresses starting from the requesting client. If not
specified, the default of x-forwarded-for is used.

internalProxies

Regular expression (using java.util.regex) that a
proxy's IP address must match to be considered an internal proxy.
Internal proxies that appear in the remoteIpHeader will
be trusted and will not appear in the proxiesHeader
value. If not specified the default value of
10\.\d{1,3}\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|169\.254\.\d{1,3}\.\d{1,3}|127\.\d{1,3}\.\d{1,3}\.\d{1,3}|172\.1[6-9]{1}\.\d{1,3}\.\d{1,3}|172\.2[0-9]{1}\.\d{1,3}\.\d{1,3}|172\.3[0-1]{1}\.\d{1,3}\.\d{1,3}|0:0:0:0:0:0:0:1
will be used.

proxiesHeader

Name of the HTTP header created by this valve to hold the list of
proxies that have been processed in the incoming
remoteIpHeader. If not specified, the default of
x-forwarded-by is used.

requestAttributesEnabled

Set to true to set the request attributes used by
AccessLog implementations to override the values returned by the
request for remote address, remote host, server port and protocol.
Request attributes are also used to enable the forwarded remote address
to be displayed on the status page of the Manager web application.
If not set, the default value of true will be used.

trustedProxies

Regular expression (using java.util.regex) that a
proxy's IP address must match to be considered an trusted proxy.
Trusted proxies that appear in the remoteIpHeader will
be trusted and will appear in the proxiesHeader value.
If not specified, no proxies will be trusted.

protocolHeader

Name of the HTTP Header read by this valve that holds the protocol
used by the client to connect to the proxy. If not specified, the
default of null is used.

portHeader

Name of the HTTP Header read by this valve that holds the port
used by the client to connect to the proxy. If not specified, the
default of null is used.

protocolHeaderHttpsValue

Value of the protocolHeader to indicate that it is
an HTTPS request. If not specified, the default of https is
used.

httpServerPort

Value returned by ServletRequest.getServerPort()
when the protocolHeader indicates http
protocol and no portHeader is present. If not
specified, the default of 80 is used.

httpsServerPort

Value returned by ServletRequest.getServerPort()
when the protocolHeader indicates https
protocol and no portHeader is present. If not
specified, the default of 443 is used.

changeLocalPort

If true, the value returned by
ServletRequest.getLocalPort() and
ServletRequest.getServerPort() is modified by the this
valve. If not specified, the default of false is used.

SSL Valve

Introduction

When using mod_proxy_http, the client SSL information is not included in
the protocol (unlike mod_jk and mod_proxy_ajp). To make the client SSL
information available to Tomcat, some additional configuration is required.
In httpd, mod_headers is used to add the SSL information as HTTP headers. In
Tomcat, this valve is used to read the information from the HTTP headers and
insert it into the request.

Note: Ensure that the headers are always set by httpd for all requests to
prevent a client spoofing SSL information by sending fake headers.

Attributes

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.SSLValve.

sslClientCertHeader

Allows setting a custom name for the ssl_client_cert header.
If not specified, the default of ssl_client_cert is
used.

sslCipherHeader

Allows setting a custom name for the ssl_cipher header.
If not specified, the default of ssl_cipher is
used.

sslSessionIdHeader

Allows setting a custom name for the ssl_session_id header.
If not specified, the default of ssl_session_id is
used.

sslCipherUserKeySizeHeader

Allows setting a custom name for the ssl_cipher_usekeysize header.
If not specified, the default of ssl_cipher_usekeysize is
used.

Single Sign On Valve

Introduction

The Single Sign On Valve is utilized when you wish to give users
the ability to sign on to any one of the web applications associated with
your virtual host, and then have their identity recognized by all other
web applications on the same virtual host.

See the Single Sign On special
feature on the Host element for more information.

Attributes

The Single Sign On Valve supports the following
configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.SingleSignOn.

requireReauthentication

Default false. Flag to determine whether each request needs to be
reauthenticated to the security Realm. If "true", this
Valve uses cached security credentials (username and password) to
reauthenticate to the Realm each request associated
with an SSO session. If "false", the Valve can itself authenticate
requests based on the presence of a valid SSO cookie, without
rechecking with the Realm.

cookieDomain

Sets the host domain to be used for sso cookies.

Authentication

The valves in this section implement
org.apache.catalina.Authenticator interface.

Basic Authenticator Valve

Introduction

The Basic Authenticator Valve is automatically added to
any Context that is configured to use BASIC
authentication.

If any non-default settings are required, the valve may be configured
within Context element with the required
values.

Attributes

The Basic Authenticator Valve supports the following
configuration attributes:

Attribute

Description

alwaysUseSession

Should a session always be used once a user is authenticated? This
may offer some performance benefits since the session can then be used
to cache the authenticated Principal, hence removing the need to
authenticate the user via the Realm on every request. This may be of
help for combinations such as BASIC authentication used with the
JNDIRealm or DataSourceRealms. However there will also be the
performance cost of creating and GC'ing the session. If not set, the
default value of false will be used.

cache

Should we cache authenticated Principals if the request is part of an
HTTP session? If not specified, the default value of true
will be used.

changeSessionIdOnAuthentication

Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of true will be
used.

charset

Controls if the WWW-Authenticate HTTP header includes a
charset authentication parameter as per RFC 7617. The only
permitted options are null, the empty string and
UTF-8. If UTF-8 is specified then the
charset authentication parameter will be sent with that
value and the provided user name and optional password will be converted
from bytes to characters using UTF-8. Otherwise, no charset
authentication parameter will be sent and the provided user name and
optional password will be converted from bytes to characters using
ISO-8859-1. The default value is null

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.BasicAuthenticator.

disableProxyCaching

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.

securePagesWithPragma

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache.
If not set, the default value of false will be used.

secureRandomAlgorithm

Name of the algorithm to use to create the
java.security.SecureRandom instances that generate session
IDs. If an invalid algorithm and/or provider is specified, the platform
default provider and the default algorithm will be used. If not
specified, the default algorithm of SHA1PRNG will be used. If the
default algorithm is not supported, the platform default will be used.
To specify that the platform default should be used, do not set the
secureRandomProvider attribute and set this attribute to the empty
string.

secureRandomClass

Name of the Java class that extends
java.security.SecureRandom to use to generate SSO session
IDs. If not specified, the default value is
java.security.SecureRandom.

secureRandomProvider

Name of the provider to use to create the
java.security.SecureRandom instances that generate SSO
session IDs. If an invalid algorithm and/or provider is specified, the
platform default provider and the default algorithm will be used. If not
specified, the platform default provider will be used.

jaspicCallbackHandlerClass

Name of the Java class of the
javax.security.auth.callback.CallbackHandler implementation
which should be used by JASPIC. If none is specified the default
org.apache.catalina.authenticator.jaspic.CallbackHandlerImpl
will be used.

Digest Authenticator Valve

Introduction

The Digest Authenticator Valve is automatically added to
any Context that is configured to use DIGEST
authentication.

If any non-default settings are required, the valve may be configured
within Context element with the required
values.

Attributes

The Digest Authenticator Valve supports the following
configuration attributes:

Attribute

Description

alwaysUseSession

Should a session always be used once a user is authenticated? This
may offer some performance benefits since the session can then be used
to cache the authenticated Principal, hence removing the need to
authenticate the user via the Realm on every request. This may be of
help for combinations such as BASIC authentication used with the
JNDIRealm or DataSourceRealms. However there will also be the
performance cost of creating and GC'ing the session. If not set, the
default value of false will be used.

cache

Should we cache authenticated Principals if the request is part of an
HTTP session? If not specified, the default value of false
will be used.

changeSessionIdOnAuthentication

Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of true will be
used.

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.DigestAuthenticator.

disableProxyCaching

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.

key

The secret key used by digest authentication. If not set, a secure
random value is generated. This should normally only be set when it is
necessary to keep key values constant either across server restarts
and/or across a cluster.

nonceCacheSize

To protect against replay attacks, the DIGEST authenticator tracks
server nonce and nonce count values. This attribute controls the size
of that cache. If not specified, the default value of 1000 is used.

nonceCountWindowSize

Client requests may be processed out of order which in turn means
that the nonce count values may be processed out of order. To prevent
authentication failures when nonce counts are presented out of order
the authenticator tracks a window of nonce count values. This attribute
controls how big that window is. If not specified, the default value of
100 is used.

nonceValidity

The time, in milliseconds, that a server generated nonce will be
considered valid for use in authentication. If not specified, the
default value of 300000 (5 minutes) will be used.

opaque

The opaque server string used by digest authentication. If not set, a
random value is generated. This should normally only be set when it is
necessary to keep opaque values constant either across server restarts
and/or across a cluster.

securePagesWithPragma

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache.
If not set, the default value of false will be used.

secureRandomAlgorithm

Name of the algorithm to use to create the
java.security.SecureRandom instances that generate session
IDs. If an invalid algorithm and/or provider is specified, the platform
default provider and the default algorithm will be used. If not
specified, the default algorithm of SHA1PRNG will be used. If the
default algorithm is not supported, the platform default will be used.
To specify that the platform default should be used, do not set the
secureRandomProvider attribute and set this attribute to the empty
string.

secureRandomClass

Name of the Java class that extends
java.security.SecureRandom to use to generate SSO session
IDs. If not specified, the default value is
java.security.SecureRandom.

secureRandomProvider

Name of the provider to use to create the
java.security.SecureRandom instances that generate SSO
session IDs. If an invalid algorithm and/or provider is specified, the
platform default provider and the default algorithm will be used. If not
specified, the platform default provider will be used.

validateUri

Should the URI be validated as required by RFC2617? If not specified,
the default value of true will be used. This should
normally only be set when Tomcat is located behind a reverse proxy and
the proxy is modifying the URI passed to Tomcat such that DIGEST
authentication always fails.

jaspicCallbackHandlerClass

Name of the Java class of the
javax.security.auth.callback.CallbackHandler implementation
which should be used by JASPIC. If none is specified the default
org.apache.catalina.authenticator.jaspic.CallbackHandlerImpl
will be used.

Form Authenticator Valve

Introduction

The Form Authenticator Valve is automatically added to
any Context that is configured to use FORM
authentication.

If any non-default settings are required, the valve may be configured
within Context element with the required
values.

Attributes

The Form Authenticator Valve supports the following
configuration attributes:

Attribute

Description

changeSessionIdOnAuthentication

Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of true will be
used.

characterEncoding

Character encoding to use to read the username and password parameters
from the request. If not set, the encoding of the request body will be
used.

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.FormAuthenticator.

disableProxyCaching

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.

landingPage

Controls the behavior of the FORM authentication process if the
process is misused, for example by directly requesting the login page
or delaying logging in for so long that the session expires. If this
attribute is set, rather than returning an error response code, Tomcat
will redirect the user to the specified landing page if the login form
is submitted with valid credentials. For the login to be processed, the
landing page must be a protected resource (i.e. one that requires
authentication). If the landing page does not require authentication
then the user will not be logged in and will be prompted for their
credentials again when they access a protected page.

securePagesWithPragma

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache.
If not set, the default value of false will be used.

secureRandomAlgorithm

Name of the algorithm to use to create the
java.security.SecureRandom instances that generate session
IDs. If an invalid algorithm and/or provider is specified, the platform
default provider and the default algorithm will be used. If not
specified, the default algorithm of SHA1PRNG will be used. If the
default algorithm is not supported, the platform default will be used.
To specify that the platform default should be used, do not set the
secureRandomProvider attribute and set this attribute to the empty
string.

secureRandomClass

Name of the Java class that extends
java.security.SecureRandom to use to generate SSO session
IDs. If not specified, the default value is
java.security.SecureRandom.

secureRandomProvider

Name of the provider to use to create the
java.security.SecureRandom instances that generate SSO
session IDs. If an invalid algorithm and/or provider is specified, the
platform default provider and the default algorithm will be used. If not
specified, the platform default provider will be used.

jaspicCallbackHandlerClass

Name of the Java class of the
javax.security.auth.callback.CallbackHandler implementation
which should be used by JASPIC. If none is specified the default
org.apache.catalina.authenticator.jaspic.CallbackHandlerImpl
will be used.

SSL Authenticator Valve

Introduction

The SSL Authenticator Valve is automatically added to
any Context that is configured to use SSL
authentication.

If any non-default settings are required, the valve may be configured
within Context element with the required
values.

Attributes

The SSL Authenticator Valve supports the following
configuration attributes:

Attribute

Description

cache

Should we cache authenticated Principals if the request is part of an
HTTP session? If not specified, the default value of true
will be used.

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.SSLAuthenticator.

changeSessionIdOnAuthentication

Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of true will be
used.

disableProxyCaching

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.

securePagesWithPragma

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache.
If not set, the default value of false will be used.

secureRandomAlgorithm

Name of the algorithm to use to create the
java.security.SecureRandom instances that generate session
IDs. If an invalid algorithm and/or provider is specified, the platform
default provider and the default algorithm will be used. If not
specified, the default algorithm of SHA1PRNG will be used. If the
default algorithm is not supported, the platform default will be used.
To specify that the platform default should be used, do not set the
secureRandomProvider attribute and set this attribute to the empty
string.

secureRandomClass

Name of the Java class that extends
java.security.SecureRandom to use to generate SSO session
IDs. If not specified, the default value is
java.security.SecureRandom.

secureRandomProvider

Name of the provider to use to create the
java.security.SecureRandom instances that generate SSO
session IDs. If an invalid algorithm and/or provider is specified, the
platform default provider and the default algorithm will be used. If not
specified, the platform default provider will be used.

jaspicCallbackHandlerClass

Name of the Java class of the
javax.security.auth.callback.CallbackHandler implementation
which should be used by JASPIC. If none is specified the default
org.apache.catalina.authenticator.jaspic.CallbackHandlerImpl
will be used.

SPNEGO Valve

Introduction

The SPNEGO Authenticator Valve is automatically added to
any Context that is configured to use SPNEGO
authentication.

If any non-default settings are required, the valve may be configured
within Context element with the required
values.

Attributes

The SPNEGO Authenticator Valve supports the following
configuration attributes:

Attribute

Description

applyJava8u40Fix

A fix introduced in Java 8 update 40 (
JDK-8048194)
onwards broke SPNEGO authentication for IE with Tomcat running on
Windows 2008 R2 servers. This option enables a work-around that allows
SPNEGO authentication to continue working. The work-around should not
impact other configurations so it is enabled by default. If necessary,
the workaround can be disabled by setting this attribute to
false.

alwaysUseSession

Should a session always be used once a user is authenticated? This
may offer some performance benefits since the session can then be used
to cache the authenticated Principal, hence removing the need to
authenticate the user on every request. This will also help with clients
that assume that the server will cache the authenticated user. However
there will also be the performance cost of creating and GC'ing the
session. For an alternative solution see
noKeepAliveUserAgents. If not set, the default value of
false will be used.

cache

Should we cache authenticated Principals if the request is part of an
HTTP session? If not specified, the default value of true
will be used.

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.SpnegoAuthenticator.

changeSessionIdOnAuthentication

Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of true will be
used.

disableProxyCaching

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.

loginConfigName

The name of the JAAS login configuration to be used to login as the
service. If not specified, the default of
com.sun.security.jgss.krb5.accept is used.

noKeepAliveUserAgents

Some clients (not most browsers) expect the server to cache the
authenticated user information for a connection and do not resend the
credentials with every request. Tomcat will not do this unless an HTTP
session is available. A session will be available if either the
application creates one or if alwaysUseSession is enabled
for this Authenticator.

As an alternative to creating a session, this attribute may be used
to define the user agents for which HTTP keep-alive is disabled. This
means that a connection will only used for a single request and hence
there is no ability to cache authenticated user information per
connection. There will be a performance cost in disabling HTTP
keep-alive.

The attribute should be a regular expression that matches the entire
user-agent string, e.g. .*Chrome.*. If not specified, no
regular expression will be defined and no user agents will have HTTP
keep-alive disabled.

securePagesWithPragma

Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache.
If not set, the default value of false will be used.

secureRandomAlgorithm

Name of the algorithm to use to create the
java.security.SecureRandom instances that generate session
IDs. If an invalid algorithm and/or provider is specified, the platform
default provider and the default algorithm will be used. If not
specified, the default algorithm of SHA1PRNG will be used. If the
default algorithm is not supported, the platform default will be used.
To specify that the platform default should be used, do not set the
secureRandomProvider attribute and set this attribute to the empty
string.

secureRandomClass

Name of the Java class that extends
java.security.SecureRandom to use to generate SSO session
IDs. If not specified, the default value is
java.security.SecureRandom.

secureRandomProvider

Name of the provider to use to create the
java.security.SecureRandom instances that generate SSO
session IDs. If an invalid algorithm and/or provider is specified, the
platform default provider and the default algorithm will be used. If not
specified, the platform default provider will be used.

storeDelegatedCredential

Controls if the user' delegated credential will be stored in
the user Principal. If available, the delegated credential will be
available to applications (e.g. for onward authentication to external
services) via the org.apache.catalina.realm.GSS_CREDENTIAL
request attribute. If not set, the default value of true
will be used.

jaspicCallbackHandlerClass

Name of the Java class of the
javax.security.auth.callback.CallbackHandler implementation
which should be used by JASPIC. If none is specified the default
org.apache.catalina.authenticator.jaspic.CallbackHandlerImpl
will be used.

Error Report Valve

Introduction

The Error Report Valve is a simple error handler
for HTTP status codes that will generate and return HTML error pages. It can
also be configured to return pre-defined static HTML pages for specific
status codes and/or exception types.

NOTE: Disabling both showServerInfo and showReport will
only return the HTTP status code and remove all CSS from the default
response.

Attributes

The Error Report Valve supports the following
configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.ErrorReportValve to use the
default error report valve.

errorCode.nnn

The location of the UTF-8 encoded HTML file to return for the HTTP
error code represented by nnn. For example,
errorCode.404 specifies the file to return for an HTTP 404
error. The location may be relative or absolule. If relative, it must be
relative to $CATALINA_BASE. The special value of
errorCode.0 may be used to define a default error page to
be used if no error page is defined for a status code. If no matching
error page is found, the default Error Report Valve
response will be returned.

exceptionType.fullyQualifiedClassName

The location of the UTF-8 encoded HTML file to return if an error has
occurred and the javax.servlet.error.exception request
attribute has been set to an instance of
fullyQualifiedClassName or a sub-class of it. For example,
errorCode.java.io.IOException specifies the file to return
for an IOException. The location may be relative or
absolule. If relative, it must be relative to
$CATALINA_BASE. If no matching error page is found, the
default Error Report Valve response will be
returned.

showReport

Flag to determine if the error report (custom error message and/or
stack trace) is presented when an error occurs. If set to
false, then the error report is not returned in the HTML
response.
Default value: true

showServerInfo

Flag to determine if server information is presented when an error
occurs. If set to false, then the server version is not
returned in the HTML response.
Default value: true

Crawler Session Manager Valve

Introduction

Web crawlers can trigger the creation of many thousands of sessions as
they crawl a site which may result in significant memory consumption. This
Valve ensures that crawlers are associated with a single session - just like
normal users - regardless of whether or not they provide a session token
with their requests.

This Valve may be used at the Engine, Host or
Context level as required. Normally, this Valve would be used
at the Engine level.

If used in conjunction with Remote IP valve then the Remote IP valve
should be defined before this valve to ensure that the correct client IP
address is presented to this valve.

Attributes

The Crawler Session Manager Valve supports the
following configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.CrawlerSessionManagerValve.

contextAware

Flag to use the context name together with the client IP to
identify the session to re-use. Can be combined with hostAware.
Default value: true

crawlerIps

Regular expression (using java.util.regex) that client
IP is matched against to determine if a request is from a web crawler.
By default such regular expression is not set.

crawlerUserAgents

Regular expression (using java.util.regex) that the user
agent HTTP request header is matched against to determine if a request
is from a web crawler. If not set, the default of
.*[bB]ot.*|.*Yahoo! Slurp.*|.*Feedfetcher-Google.* is used.

hostAware

Flag to use the configured host together with the client IP to
identify the session to re-use. Can be combined with contextAware.
Default value: true

sessionInactiveInterval

The minimum time in seconds that the Crawler Session Manager Valve
should keep the mapping of client IP to session ID in memory without any
activity from the client. The client IP / session cache will be
periodically purged of mappings that have been inactive for longer than
this interval. If not specified the default value of 60
will be used.

Stuck Thread Detection Valve

Introduction

This valve allows to detect requests that take a long time to process,
which might indicate that the thread that is processing it is stuck.
Additionally it can optionally interrupt such threads to try and unblock
them.

When such a request is detected, the current stack trace of its thread is
written to Tomcat log with a WARN level.

The IDs and names of the stuck threads are available through JMX in the
stuckThreadIds and stuckThreadNames attributes.
The IDs can be used with the standard Threading JVM MBean
(java.lang:type=Threading) to retrieve other information
about each stuck thread.

Attributes

The Stuck Thread Detection Valve supports the
following configuration attributes:

Attribute

Description

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.StuckThreadDetectionValve.

threshold

Minimum duration in seconds after which a thread is considered stuck.
Default is 600 seconds. If set to 0, the detection is disabled.

Note: since the detection (and optional interruption) is done in the
background thread of the Container (Engine, Host or Context) declaring
this Valve, the threshold should be higher than the
backgroundProcessorDelay of this Container.

interruptThreadThreshold

Minimum duration in seconds after which a stuck thread should be
interrupted to attempt to "free" it.

Note that there's no guarantee that the thread will get unstuck.
This usually works well for threads stuck on I/O or locks, but is
probably useless in case of infinite loops.

Default is -1 which disables the feature. To enable it, the value
must be greater or equal to threshold.

Semaphore Valve

Introduction

The Semaphore Valve is able to limit the number of
concurrent request processing threads.

org.apache.catalina.valves.SemaphoreValve provides
methods which may be overridden by a subclass to customize behavior:

controlConcurrency may be overridden to add
conditions;

permitDenied may be overridden to add error handling
when a permit isn't granted.

Attributes

The Semaphore Valve supports the following
configuration attributes:

Attribute

Description

block

Flag to determine if a thread is blocked until a permit is available.
The default value is true.

className

Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.SemaphoreValve.

concurrency

Concurrency level of the semaphore. The default value is
10.

fairness

Fairness of the semaphore. The default value is
false.

interruptible

Flag to determine if a thread may be interrupted until a permit is
available. The default value is false.